add named volume to lnd service for persisting data accross container…

[yancyribbens]

Add a named volume to docker-compose.yml for persisting lnd application volume state. Without this volume, if the container is brought down (for example using docker-compose down) the state is lost, and lnd needs to resync, eg:

lnd_btc | 2019-01-18 16:38:41.154 [INF] LNWL: Caught up to height 10000

Adding this volume will persist the state along with btc similar to how a local install would work. The new volume can be inspected using docker volume inspect docker_lnd . Using a named volume in docker-compose allows docker to re-attach to the named volume during docker up. This is preferable to an anonymous volume which isn't recognized by docker-compose and so this PR replaces #2507

[halseth]

Does this also replace #697?

[yancyribbens]

Yes unless you prefer to cherry pick from #697 instead. When I opened #2507 I wasn't aware of #697.

[halseth]

This is a much simpler change, so i would prefer sticking to this.

[yancyribbens]

SGTM

[halseth]

utACK 👍

[darwin]

This is definitely needed. I based my mainnet lnd setup on these docker scripts and did this change when tweaking it. But there is one additional subtle change you should make.

You should remove custom --logdir

lnd/docker/lnd/start-lnd.sh

Line 54 in 2b43da4

--logdir="/data" \

By default, lnd logs into lnd's data folder /root/.lnd/logs/... which is what you want because that folder is mapped to host directory and persists. Logging into forced /data inside container would not persist logs between container rebuilds. Logs are not a big issue with simnet, but if someone took your setup (like I did) and based mainnet lnd setup on it, this could be an easy mistake.

[yancyribbens]

Thanks @darwin. I've updated the PR to use the default home directory.

[guggero]

Sorry this has been lying around for so long. We'll be putting more focus on Docker stuff in the future.

There's a small nit in the comment.
And could you please also squash the two commits and a docker: prefix to the commit message?

[guggero]

Thanks for the changes! I tested the tutorial again and it works as expected.

Something went wrong with the commits, now there are 5 instead of one. Feel free to ping me on Slack if you need help with git.

[yancyribbens]

@guggero sure no problem! i'll rebase the commit history and ping you if needed.

[yancyribbens]

@guggero comments have been squashed

[guggero]

LGTM 👍